Grease cup



July 10, 1928. 7 1,676,523

E. CONRAD GREASE our Filed May 4, 1926 Patented July 10, 1928.

g ururizo s'rarss 1,676,523 PATENT. OFFHCE.

EWALD CONRAD, 0F Q'U'ASNITZ, NEAR LEIPZIG, GERMANY, ASSIGNOR TO THE FIRM AKTIEN-GESELLSCHAFT FUR SCHMIERTECHNIK, OF LEIIPZIG, GERMANY.

GREASE our.-

Application filed May 4, 1926, Serial No. 106,630, and in Germany May 9, 1925.

Grease cups from which the grease is expelled by compressed air are known. This kind of grease cup comprises a container having an outlet for the grease, a disc to rest on the grease in said container, and a domed cap adapted to be screwed into said container. When the cap is screwed into the container (while the outlet is closed or obstructed) the air imprisoned in the cap is compressed and (after the nozzle is opened) this air pressure comes into action to force out the grease.

I have found that the air pressure falls rather quickly and that, in practice, the grease is expelled, too rapidly towards the bearing to be lubricated; the compressed air penetrates between the rim of the disc and the internal wall of the container, forces its way through the grease and escapes through the grease outlet.

To prevent the grease from being forced out too quickly, it has been proposed to divide the cap into two chambers by a partition and make communication between them only by way of a small hole inthat partition (see German patent to this applicant No. 384,096, October 25, 1923). The effect intended is that when the cap is screwed into the container, only the air contained in the outer of said chambers shall undergo compression at first, the air pressure gradually becoming equalized in the inner chamber; while in emptying the cup, the air pressure in the outer chamber shall come first into action and a gradual equalization take place by the compressed air in the inner chamber. In this way it is intended that the grease shall be discharged in a fairly uniform manner, in accordance with the consumption in the hearing. In this cup the disc that rests on the surface of the grease is suspended from the partition by means of a wire extending through the aforesaid small hole. The disc is firmly secured to the wire and the wire penetrates into the inner cham her as the cap is screwed home. Consequently, the length of the inner chamber must correspond to that of the outer chamber.

With this type of grease cup a high initial or charging pressure cannot be obtained because of the fact that the two chambers are of equal size: indeed this pressure is little in excess of one atmosphere when the cap is screwed home. Moreover, in order to allow the play necessary for the easy movement of the guided wire, the open ng 1n the partition has to be .too large, so'that the pressures in the two chambers become equal very rapidly. My present invention obviates these defects. The novelty consists in that the partition is rigidly connected to the disc resting onthe grease, so that the two form, in combination, a hollow piston. arrangement the communicating opening in the piston between the one air chamber (located in the cap) and the other air chamber (now located in the piston) is of capillary dimensions.

A typical embodiment is shown, in cross section. on the accompanying drawing to which reference will now be made.

a denotes the grease container, terminating in an externally threaded discharge nozzle 0 and f is the cap that screws into said container.

y A shallow hollow piston 0 is slidably fitted into the cap so as to be air-tight. The upper face of the hollow piston is provided with a capillary opening 39 and the lower face is provided with a strap 9 serving as a handle.

To prepare the grease cup for use, the container a is carefully and compactly filled with grease up to the rim, and after the hollow piston 0 has been inserted in the cap 7 so as to project slightly, said cap is put into position. On screwing the cap into the container while the nozzle 0 is closed (preferably by a tap or the like, not shown, usually provided for that purpose) the grease is forced into the cap and pushes back the hollow piston 0 into same, thus compressing the air. The compression in the interior of the hollow piston 0 (that isin the space of constant dimensions) proceeds more slowly (by reason of the small size of the communicating passage 2) than in the interior of the cap f- (that is in the chamber of variable dimensions) in accordance with the laws governing the rate of outflow through nozzles. Sald compression is, however, greater than in the known grease cup hereinbefore described because, owing to the low height of the hollow piston o the total air is compressible into a substantialy smaller space.

On freeing the delivery nozzle of the con tainer a the air pressure forces the grease out gradually in the form of a rope, while at the same time, a gradual mutual balancing With this A of pressure takes place from the interior of the hollow piston 0 towards the overlying chamber, until they are both at approximately atmospheric pressure. Owing to the greater initial pressure, the grease cup continues to operate longer than those hitherto known. Moreover, the delivery of the grease to the point of application is not only governed by the pressure obtaining in the cup, the grease being also drawn onward by the capillary action of the machine part which is being lubricated. This action, however, is rendered possible by the elastic compression effect of the air cushion.

pelled by compressed air, comprising a container having an outlet for the grease, a cap adapted to be forced into the cup to compress the air, and a hollow piston fitted into the cap, said piston having a small opening of capillary dimensions in its upper surface to gradually equal ze air pressure.

2. A grease cup of that type in which grease is expelled by compressed air, comprising a container having'an outlet for the grease, a cap adapted to be forced into the same to expel thegrease by air compression, and an intervening hollow piston adapted to rest on the surface of the grease and being airtightly fitted to slide in said cap, said p'ston having a minute air-hole in its upper surface.

In test mony whereof I aflix my signature.

EWALD CONRAD. 

